英语语法分析

It consists of a base (the alidade) on which a sight is mounted. When this is horizontal, its axis is parallel to the base.

在(照准仪)基座上水平且与台基座平行地装有一镜。

Table Alidade, Instrument used on the board for drafting topographical charts in order to indicate the angles between two points.

台上用照准仪，在绘图台上使用的工具，用作之处两点间的角度。

A flat drawing board mounted on a tripod used in combination with an alidade to construct topographic or geologic maps in the field.

一块安装在一个三脚架上的平坦画板，与照准仪一起用于在野外测制地形图或地质图。